Preparation and Tribological Properties of Dual-Coated TiO₂ Nanoparticles as Water-Based Lubricant Additives

Figure 4

SEM micrographs of wear scar surfaces lubricated with different concentration of nanoparticles: (a) no addition, (b) 0.1 vt.%, (c) 0.8 vt.%, and (d) 1.6 vt.%.